HP Notebook PC (AMD) HP 255 G4 Notebook PC - Maintenance and Service Guide
Heat sink assembly
NOTE: The heat sink assembly spare part kit includes replacement thermal materials.
Description Spare part number
Heat sink for use in models with discrete graphics memory 813948-001
Heat sink for use in models with UMA 813947-001
NOTE: To properly ventilate the computer, allow at least 7.6 cm (3.0 in) of clearance on the left side of the
computer. The computer uses an electric fan for ventilation. The fan is controlled by a temperature sensor and
is designed to turn on automatically when high temperature conditions exist. These conditions are aected by
high external temperatures, system power consumption, power management/battery conservation
congurations, battery fast charging, and software requirements. Exhaust air is displaced through the
ventilation grill located on the left side of the computer.
Before removing the heat sink assembly, follow these steps:
1. Shut down the computer. If you are unsure whether the computer is o or in Hibernation, turn the
computer on, and then shut it down through the operating system.
2. Disconnect all external devices connected to the computer.
3. Disconnect the power from the computer by rst unplugging the power cord from the AC outlet and then
unplugging the AC adapter from the computer.
4. Remove the battery (see Battery on page 30).
5. Remove the optical drive (see Optical drive on page 31), if installed.
6. Remove the bottom cover (see Bottom cover on page 37).
To remove the heat sink assembly:
1. Refer to the following heat sink removal image that matches your computer.
2. Loosen the screws on the heat sink that secure the heat sink assembly to the system board.
Component replacement procedures 49